Rod Gilmour on the American diver's return to the US team as a mentor.

It was one of the defining images of the 1988 Olympics. The moment of impact when Greg Louganis’s head hit the 3m springboard in Seoul as he attempted a reverse 2½ somersault pike position. What followed, though, made headlines long after the Olympics had left town.

Louganis fell into the water, blood spilling from the back of his head. He climbed out of the pool and Jim Puffer, the United States team doctor, sewed five stitches into the wound. Louganis was leading the event after the preliminary rounds and looked a safe bet to win the competition – but at that moment he felt his world collapsing.

Having tested HIV positive six months before the Games, he knew he had a duty to tell the authorities as drops of blood dissolved in the water. He knew what he had to do, but he could not bring himself to do it. He had kept his homosexuality and his HIV a secret thus far, and wanted his diving success and not his illness to be the story of Seoul.

“I was paralysed by fear after Dr Puffer sewed up my head,” Louganis recalls. “I thought not only was I going to suffer the agony of defeat, I also felt tremendous guilt. Ron O’Brien [Louganis’s coach] gave me an option. He said no one would be blaming me if I didn’t go back up there and dive.” But Louganis did go back up.

“It turned out to be a mixed blessing,” he says. “I was heavy favourite but in a split second I became the underdog. It was an easier position to come from because the expectations weren’t there.”

Louganis says he found inspiration in Ryan White, who became one of the first children to develop Aids, in 1984, and whom he had tried to bring to Seoul as a lucky mascot. “It was during a tough time when there was no compassion surrounding HIV. I tried to get Ryan to share my Olympic experience under the friends-and-family programme but he was denied a visa due to his HIV status.”

Louganis won the gold and a week later won a second, after a dramatic tussle with China’s 14-year-old prodigy Xiong Ni in the 10-metre platform. He thus became, at 28, the first man to win back-to-back Olympic titles after his 1984 success. The US boycott of the 1980 Moscow Games probably denied him a hat‑trick of Olympic golds.

His success was a world away from his early life, which had already been blighted by problems after being given up for adoption at nine months by his Samoan father and European mother, who were just 15 when he was born. A dyslexic, he suffered bullying and racism at school in California. By the age of 16 he was doing speed, sold marijuana, considered himself an alcoholic and thought about suicide.

The Olympics appeared to be his salvation but hard times were never far away during his early life. He had been in an abusive relationship since 1983 and it worsened after his return from Korea.

Finally, in 1994, he came out. A best-selling book Breaking the Surface followed, in which details emerged of his secrets prior to the 1988 Games. He was widely criticised for allowing the doctor to check him without gloves – Dr Puffer subsequently tested negative for HIV – but at last he was free from self-doubt.

The reaction did not surprise him. He says he “never felt welcome” after coming out and reckons the US Olympic team deprived him of the chance of being involved after his retirement. Until now.

At the age of 50, Louganis has returned to the US team as a diving mentor and helped at the US Grand Prix in Fort Lauderdale in May. “It’s great to be back, there’s no doubt about that,” he says, his famously handsome features now framed by flowing silver hair.

He says he is hoping to nurture the team to Olympic success following abject performances at the 2004 and 2008 Games where American divers failed to win a medal. The goal is simply for a team or individual to reach the podium in 2012. It’s a modest but realistic target considering Team USA’s last diving medal was a bronze at the 2000 Sydney Games.

The long overdue call came from Australian Steve Foley, a three-time Olympian and former rival, who left his post as performance director at British Diving to take up a similar role at US Diving last year.

“There is talent within the US team, but they need to focus on the right areas,” he says. “The current global state of diving is the world chasing China. For the most part you have that rare talent like Russia’s Dmitri Sautin, Australia’s Matthew Mitcham [Beijing gold medallist] and Tom Daley. We have those sporadic talents knocking on the door but China are still very smart.”

So much so that they took the Louganis template to full effect back in the Eighties. “They used me as a model. I was dancing and doing acrobatics when I was 18 months old and I was performing on stage when I was three. China now have their own model with dramatic improvements.”

Louganis reserves high praise for Daley, 16, Britain’s great medal hope for London 2012, and hopes to meet the Plymouth diver when the world junior titles come to Arizona in September.

“I saw him at Beijing in 2008 and have seen some YouTube clippings but this will be the first time I will have met him. When you get to that level you know who the top divers are and who can put performances together. It is not about USA versus England or China. It is about pushing you to your edges, which is what Tom is clearly trying to do. I would be there in a heartbeat to help him if he came calling.”